Method of treating rocks containing potassium.



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ALLEBTON S. CUSI'l'l/fillf, QF WASHINGTON, DISTRICT OF COLUMBTA.

METHOD OF TI-tEATINGR-OCKS CONTAINING POTASSIUTIL To all whom it mayconcern:

lie it known that I, Annnnrou CUSTL.

Man, a citizen of the United States, residing at Washin c'ton, in theDistrict of Columbia, have invented certain new and useful Improvementsin Iilethods of 'lreating Rocks (,ontaining; Potassium, of'which thefollowing aspccificati'on.

The object of this invention is the provision of'an ccononiical methodwhereby the potassium content of certain minerals or rocks may beconverted, partly or Wholly, into a Water-soluble state. I

The invention will be described applied to the treatment of feldspathicrocks or rainerals. which may be regarded for the purpos s of thisspecification as consisting es-, sentlally' of silicate of potassium andaluniinnni. I

Many efforts have heretofore been made to transform the potassiumcontained in orthoclose and similar minerals into a watereoluble,condition, but in no case, so far as I am aware, have such efforts beenconnnercially successful. The reaction itself whereby the feldspars aredecomposed in presence of lime, or of lime and sodium chlorid. presentsno particular difiiculties on a laboratory scale-and at a fusingtemperature, but has heretofore proven quite impracticable from acommercial point of View. I have now discovered that it is possible totrans form a commercially important quantity of the potassium containedin feldspars and other pot'assiuni-bc:n'ing rocks into a Watersolublecondition, under conditions which render possible the economical andcontinuous treatment: of large quantities of material.

As a specific example of my invention 1 may proceed as follows: Thefeldspar 0r feldspathic rock is first reduced to as fine subdivision asis practicable, preferably to pass l1l1I'O1; '"l1 a screen having twohundred meshes to the linear inch. This finely pow dered material isthen uniformly mixed with a suitable proportion of finely pulverizedquicklirne. Suitable proportions for the mixture comprise parts ofground feldspar to 20 parts oflime, although the proportionof lime maybe varied within wide limits, inasmuch as its principal function isrelated to the productionof aggregates as hereinafter described. Undercertain conditions, and particularly when the subsequent furnacing iscarried out under conditions not requiring the production of extremelyhard aggregates, the lune may be entirely omitted. This pulverulentmixture is then uniformly" spread upon a suitable conveyor, as a belt ordrun'nin the form of a bed having a thickness oft-hre-eighths to onehalfinch or somewhat more. To the geurface of this bed is now applied asolution of calcium chlorid. care being preferably observed that thesolution is applied inseparate drops, so positioned with relationtoe-ach other that the aggregates formed shallhot merge or unite into asolid vmass or crust. The calciuin chlorid reactsin'n'nediately with thelime to form an oxychlorid cement by which that portion of thepowderwith which. the calcium chlorid solution comes. in contact isclumped or collected into 1 small rounded inassesor aggregates whichharden 'quickly at ordinary temperatures. These aggregates are separatedfrom thennconverted powder by screening, and after, dry ing or evenwithoutthe neccssityof drying, are further heated to a proper reactingternperature. Similar aggregates are formed in the absence of lime, butless hard. and strong than thoseprepared as above. 1 The reaction maytake placeat a dull red heat, and the temperature is preferably but notnecessarily kept below the point atwhich a substantial portion of the:.'potassiun1 chlorid formed is sublinied. The furnacing of theaggregates is best carriedout ina rotary furnace or kiln, whichmay be ofthe type used for the burning ofcement ,orlike materials. The roundedmasses progress regularly and uniformly through the kiln, and duringtheir progress andiwithout fusw ing or hitting, a reaction occurswherebya substantial proportion of the-potassium 1 content of thefeldspar is converted intone. chlorid, with simultaneous formation of asilicate of calcium. The product is discharged froin the furnace in theform of small lumps or particles,and may becrushed or ground for use asa fertilizer orasa cqrn; ponent of mixed fertilizers; or the, potassiumchloridmayhe extracted by means of water and recovered from thesolutionpr utilized thereinin any preferredwayl The freshly preparedproduct contains a qroptn'- tion of free lime which is; in generalapproxi niately the sameas thefree lime ,inthe mix;- ture beforecalcinationot i The amount and concentration;oft-the cal,- cium chloridsolution shre. determined by reference to certain factors: The amount,of calcium chlorid added should be sufficient to supply chlorin inquantities at leastn o Specificationot Letters Patent. F -ta nted lylgu', 21" 19111, Application filed Deceiiiber 1?,1910. ser ai'uo. 597,18,

3CaO.CaCl,.15H,O.

For example, 100 parts of feldspar containing 11.5% of K,O would requireapproximately 13.6 parts by weight of calcium chlorid to supply thechlorin necessary for the formation of KCl. These 13.6 parts of calciumchlorid, or preferably an amount in some excess thereof, are added insolution in 28.6 parts by weight of water, thesolution being addedpreferably drop by drop, to an excess of a. pulverized mixture offeldspar and lime in proportions of 100' 20. The above illustrativeconditions may be widely varied, it being necessary only that thechlorin should be supplied in sufiicient proportion as demanded by thereaction, and that the lumps or aggregates formed should be of suchcharacter as to endure, without breaking down into an ultimate powder,,the operations involved in their separation and furnacing. The calciumchlorid may be supplemented or in part. replaced by any other suitablealkali or alkali-earth metal chlorid; or it may be replaced undercertain conditions by salts of other mineral acids capable ofdecomposing mineral silicates of the character above described, as forexample by an alkali metal sulfate.

I do not claim broadly the above described method of preparingpulverulent charges for furnacing, and it should be understood that theaggregate may be prepared for furnacing by methods other than thatherein described, as for example by the use of pressure applied to asuitable mixture, the resulting masses or briquets being thereafterbroken or crushed to suitable size.

for furnacing.

I claim:

1. The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a watersoluble state, whichconsists in powdering the rock, forming therefrom aggregates containinga salt of a mineral acid capable of decomposing such rock, and furnacingsuch aggregates.

2. The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a watersoluble state, whichconsists in powdering the rock, forming therefrom aggregates containinga salt of a mineral acid capable of decomposing such rock, and furnacingsuch aggregates while in .motion.

3. The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a watersoluble state, whichconsistsin powdering the rock, forming therefrom aggregates containing asuitable chlorid, and furnacing' such aggregates.

4. The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a watersoluble state, whichconsists in powdering the rock, forming aggregates therefrom by theaction of calcium chlorid, and furnacing such aggregates.

The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a watersoluble state, whichconsists in powdering the rock, forming aggregates therefrom by theaction of calcium ehlorid in presence of lime, and furnacing suchaggregates.

6. The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a watersoluble state, whichconsists in powdering the rock, treating the powdered material with asolution of calcium chlorid,-thereby forming. lumps or aggregates, andfurnacing such a gre ates. V by z:

7. The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a watersoluble state, whichconsists in powdering the rock, treating the powdered material wit-h asolutionof calcium chlorid, thereby forming lumps or aggregatesassociated with residual powdered material, and furnacing theaggregates.

8. The method of treating feldspathic or similar rock for the purpose ofconverting potassium contained therein into a water soluble state, whichconsists inpowdering the rock, mixing a proportion of lime therewith,treating the powdered mixture with a solution of calcium chlorid andthereby forming aggregates associated with powdered material, separatingsuch aggregates from the powdered material, and furnacing theaggregates.

In testimony whereof, I affix my signature in presence of two witnesses.

ALLERTON s. CUSH-MAN.

Witnesses: Q

GEORGE W. CoocEsHAL CLINTON P. TOWNSEND.

' Copies of this patent may be obtained for five cents each, byaddressing the Commissioner of Patents, Washington, I). G.

